Typically, dormant seedlings are transplanted when revegetating nonirrigated disturbed lands in order to prevent transplant shock triggered by water stress. Since dormant seedlings have to be used, this limits the duration of the transplant season. It may be possible to increase this limited season by inducing acclimation responses that would increase drought tolerance. Preconditioning actively growing seedlings to water stress prior to transplanting could induce acclimation responses such as solute accumulation and/or stomatal modulation. Under greenhouse conditions, A. cana and A. intermedium seedlings were subjected to three water stress preconditioning treatments: a well watered control, one dry-down cycle, and three dry-down cycles. After conditioning, seedlings were either allowed to dry-down in their containers until leaf senescence, or were transplanted to disturbed land sites. Plant water potential components, relative water content, and leaf mortality were measured. Immediately following treatments, water relations parameters of preconditioned seedlings were not markedly different from controls in either species. At the end of the final dry-down, water stress preconditioning had not induced active or passive solute accumulation, prolonged leaf survival when exposed to lethal drought conditions, or resulted in differences in transplant survival rates under the experimental conditions of this study.

Water scarcity is a problem that will be exacerbated by climate change. Being able to model the effect of climate change on water scarcity is important to effectively plan the use of future water resources. This research integrated the Soil and Water Assessment Tool (SWAT), climate model, and water footprint analysis to measure the impact of climate change on future water scarcity. This was achieved through two objectives. The first objective was to create a modeling framework that links the output from climate model to SWAT and combined streamflow outputs from SWAT with water footprint analysis to measure how climate change will impact water scarcity of a river basin. This was accomplished through creating a SWAT model within ArcMap and inputting a topographic, soil, land use, and weather data. Climate Forecast System Reanalysis (CFSR) data were used in lieu of observed weather data due to a lack of available data. SWAT-CUP (Calibration and Uncertainty Program) was used to calibrate two upstream streamflow gauges, then calibrate and validate a third streamflow gauge at the outlet of the Senqu basin in Lesotho. The two upstream streamflow gauges were calibrated from 1986 to 2002. The downstream streamflow gauge was calibrated from 1985 to 2002 and validated from 2003 to 2013. Three Regional Climate Models (RCM), ICHEC-EC-EARTH, MIROC-MIROC5, and CCCma-CanESM2 were downloaded from the Coordinated Regional Downscaling Experiment (CORDEX) dataset. Each RCM was downloaded with two different Coupled Model Intercomparison Project (CMIP5) Representative Concentration Pathways (RCP), RCP 4.5 and RCP 8.5. The RCMs were bias corrected using a cumulative distribution function mapping technique. These RCMs as well as an average of the RCMs were used as input for the SWAT model to generate future streamflow outputs. The streamflow outputs provide the future blue water availability of the Senqu River. The results showed an overall decrease in streamflow in both RCPs. The second objective was to apply the framework to Lesotho and use the information from the ArcSWAT model and data from the Blue Water Footprint analysis to measure the future potential Blue Water Scarcity of Lesotho. This was accomplished through the Blue Water Footprint of Lesotho generated from the 5th National Blue Footprint analysis. The annual blue water scarcity was calculated as the ratio of the Blue Water Available to Blue Water Footprint. Three approaches were adopted to analyze the water scarcity of Lesotho. The first approach used the national Blue Water Footprint in the water scarcity calculation to investigate the worst-case scenario. The second approach used the modified blue water footprint based on the population living within the Senqu river basin. The third approach used a modified blue water footprint that accounted for the projected population growth of Lesotho. The results of scenario 1 showed there was moderate water scarcity in a period of four years in climate scenario of RCP8.5. The results of scenario 3 showed there were multiple cases of water scarcity in both RCP 4.5 and RCP 8.5 with two years of severe water scarcity. This research is limited by data availability and the results for Lesotho could be improved by accurate dam data and the fine scale water footprint analysis. The modeling framework integrating climate model, hydrology, and water footprint analysis, however, can be applied to other remote places where limited data are available.

Increased water scarcity due to changing climate, population growth, and economic development is a major threat to the sustainability of irrigated agriculture in the Western United States and other regions around the world. Management practices, such as controlled deficit irrigation, that seek to maximize the productivity of a limited water supply are critical. When using controlled deficit irrigation, remote sensing of crop canopy temperature is a useful tool for assessing crop water status and for more precise irrigation management. However, there is potential that nutrient deficiencies could compound the interpretation of water status from leaf temperature by altering leaf color and radiation balance. One objective of this thesis was to evaluate whether nitrogen fertility status of maize interacts with remotely sensed leaf temperature under full and limited irrigation. Another objective was to evaluate the effect of varying irrigation and nitrogen regimes on three water stress indices: Crop Water Stress Index (CWSI), Degrees Above Non-Stressed (DANS), and Degrees Above Canopy Threshold (DACT). Replicated studies were conducted using maize grown in both the glasshouse and the field. The glasshouse study consisted of combinations of well-watered and drought irrigation and sufficient and deficient nitrogen levels, while the field study consisted of combinations of well-watered, limited or controlled deficit, and drought irrigation and sufficient, sufficient delayed, and deficient nitrogen levels. In the glasshouse, leaf chlorophyll content was reduced moderately by limited irrigation and more so by N deficiency. For most observations in the glasshouse, the remotely sensed leaf temperatures were affected by irrigation, but not by N level. With drought irrigation, leaf temperature averaged 29.0° C, compared to 27.9 °C for the well-watered treatment. Similar results were observed in the field, illustrating the utility of canopy temperature in detecting water stress and that the measurement was not confounded by N status. It was also found that irrigation had a significant effect on all three water stress indices. For example, in the glasshouse, cumulative DANS was 32.2 for the drought treatment and 15.5 for the well-watered treatment. Similar results were found for other stress index measurements both in the glasshouse and the field. DANS underestimated stress on days when the reference crop was stressed and overestimated stress on low temperature days. DACT risks finding no stress when temperatures are below the canopy threshold temperature of 28.0 °C. Thus, CWSI is the most effective index, given that it takes humidity and air temperature into account. Indices were only weakly related to leaf area, biomass or grain yield, or crop water productivity. Linear regression of Nitrogen Sufficiency Index and its effect on crop growth found significant effects on biomass and grain yield, crop water productivity, and final leaf area. Thus, water stress indices are useful tools in evaluating crop water status, but consideration of other factors, such as nutrient status, must be taken for prediction of crop growth and yield.

Crops adapted to dry conditions are essential to meet future food, feed and energy needs. Knowledge of interaction between drought tolerance traits and their response to varying water supply conditions would improve selection for yield stability traits. This study focused on determining the association between the QTL regulating the staygreen trait in sorghum with improved canopy temperature depression (CTD) as regulated by total and compositional epicuticular wax content in a recombinant inbred line population derived from BTx642 and RTx7000. Phenotypic data were collected in 3 replicated field trials and 1 greenhouse trial. Plants with higher leaf EWL had cooler canopies. Our results also confirmed that staygreen genotypes are able to maintain cooler canopy than the non-stay-green genotypes under drought and hot conditions. We have suggested that wax might offer a more stable indicator for selection of drought tolerance under a variety of weather conditions. Composite interval mapping identified a total of 28 QTL, fifteen of which had significant overlaps. The overlap between QTL for cuticular leaf wax and QTL for staygreen exhibits a departure from the QTL overlaps for other traits with that of cuticular leaf wax. We have also suggested that under drought stress, the QTL for staygreen may be expressed earlier in time (at anthesis) than had been previously believed.

Global trade and increasing food demand are important drivers of impacts in the water system across scales. This study coupled a spatially-explicit physical account of trade between Brazilian municipalities with a water footprint accounting model, in order to analyse water footprints of Brazilian soy produced for domestic and international consumption, and assess their relevance in the context of water scarcity and competing demands for water resources. The water footprints of Brazilian soy production were assessed for different levels of spatial-explicitness for comparison. The Swedish water footprints were analysed within this framework to illustrate the use of the methodology. As a result, temporal and geographical patterns of variability of water the footprints related to Brazilian soy production, attributed to different consumers in the global market, were identified. The study found the methodology to unveil important processes connected to economic and trade drivers, as well as to variability in climate and production yields. It was found that important regional variability was not considered or fully understood when accounting for water footprints as a national aggregate. Opportunities for improvement and further research were also discussed.

Bananas are susceptible to a diverse range of biotic and abiotic stresses, many of which cause serious production constraints worldwide. One of the most destructive banana diseases is Fusarium wilt caused by the soil-borne fungus, Fusarium oxysporum f. sp. cubense (Foc). No effective control strategy currently exists for this disease which threatens global banana production. Although disease resistance exists in some wild bananas, attempts to introduce resistance into commercially acceptable bananas by conventional breeding have been hampered by low fertility, long generation times and association of poor agronomical traits with resistance genes. With the advent of reliable banana transformation protocols, molecular breeding is now regarded as a viable alternative strategy to generate disease-resistant banana plants. Recently, a novel strategy involving the expression of anti-apoptosis genes in plants was shown to result in resistance against several necrotrophic fungi. Further, the transgenic plants showed increased resistance to a range of abiotic stresses. In this thesis, the use of anti-apoptosis genes to generate transgenic banana plants with resistance to Fusarium wilt was investigated. Since water stress is an important abiotic constraint to banana production, the resistance of the transgenic plants to water stress was also examined. Embryogenic cell suspensions (ECS) of two commercially important banana cultivars, Grand Naine (GN) and Lady Finger (LF), were transformed using Agrobacterium with the anti-apoptosis genes, Bcl-xL, Bcl-xL G138A, Ced-9 and Bcl- 2 3’ UTR. An interesting, and potentially important, outcome was that the use of anti-apoptosis genes resulted in up to a 50-fold increase in Agrobacterium-mediated transformation efficiency of both LF and GN cells over vector controls. Regenerated plants were subjected to a complete molecular characterisation in order to detect the presence of the transgene (PCR), transcript (RT-PCR) and gene product (Western blot) and to determine the gene copy number (Southern blot). A total of 36 independently-transformed GN lines (8 x Bcl-xL, 5 x Bcl-xL G138A, 15 x Ced-9 and 8 x Bcl-2 3’ UTR) and 41 independently-transformed LF lines (8 x Bcl-xL, 7 x BclxL G138A, 13 x Ced-9 and 13 x Bcl-2 3’ UTR) were identified. The 41 transgenic LF lines were multiplied and clones from each line were acclimatised and grown under glasshouse conditions for 8 weeks to allow monitoring for phenotypic abnormalities. Plants derived from 3 x Bcl-xL, 2 x Ced-9 and 5 x Bcl-2 3’ UTR lines displayed a variety of aberrant phenotypes. However, all but one of these abnormalities were off-types commonly observed in tissue-cultured, non-transgenic banana plants and were therefore unlikely to be transgene-related. Prior to determining the resistance of the transgenic plants to Foc race 1, the apoptotic effects of the fungus on both wild-type and Bcl-2 3’ UTR-transgenic LF banana cells were investigated using rapid in vitro root assays. The results from these assays showed that apoptotic-like cell death was elicited in wild-type banana root cells as early as 6 hours post-exposure to fungal spores. In contrast, these effects were attenuated in the root cells of Bcl-2 3’ UTR-transgenic lines that were exposed to fungal spores. Thirty eight of the 41 transgenic LF lines were subsequently assessed for resistance to Foc race 1 in small-plant glasshouse bioassays. To overcome inconsistencies in rating the internal (vascular discolouration) disease symptoms, a MatLab-based computer program was developed to accurately and reliably assess the level of vascular discolouration in banana corms. Of the transgenic LF banana lines challenged with Foc race 1, 2 x Bcl-xL, 3 x Ced-9, 2 x Bcl-2 3’ UTR and 1 x Bcl-xL G138A-transgenic line were found to show significantly less external and internal symptoms than wild-type LF banana plants used as susceptible controls at 12 weeks post-inoculation. Of these lines, Bcl-2 3’ UTR-transgenic line #6 appeared most resistant, displaying very mild symptoms similar to the wild-type Cavendish banana plants that were included as resistant controls. This line remained resistant for up to 23 weeks post-inoculation. Since anti-apoptosis genes have been shown to confer resistance to various abiotic stresses in other crops, the ability of these genes to confer resistance against water stress in banana was also investigated. Clonal plants derived from each of the 38 transgenic LF banana plants were subjected to water stress for a total of 32 days. Several different lines of transgenic plants transformed with either Bcl-xL, Bcl-xL G138A, Ced-9 or Bcl-2 3’ UTR showed a delay in visual water stress symptoms compared with the wild-type control plants. These plants all began producing new growth from the pseudostem following daily rewatering for one month. In an attempt to determine whether the protective effect of anti-apoptosis genes in transgenic banana plants was linked with reactive oxygen species (ROS)-associated programmed cell death (PCD), the effect of the chloroplast-targeting, ROS-inducing herbicide, Paraquat, on wild-type and transgenic LF was investigated. When leaf discs from wild-type LF banana plants were exposed to 10 ìM Paraquat, complete decolourisation occurred after 48 hours which was confirmed to be associated with cell death and ROS production by trypan blue and 3,3-diaminobenzidine (DAB) staining, respectively. When leaf discs from the transgenic lines were exposed to Paraquat, those derived from some lines showed a delay in decolourisation, suggesting only a weak protective effect from the transgenes. Finally, the protective effect of anti-apoptosis genes against juglone, a ROS-inducing phytotoxin produced by the causal agent of black Sigatoka, Mycosphaerella fijiensis, was investigated. When leaf discs from wild-type LF banana plants were exposed to 25 ppm juglone, complete decolourisation occurred after 48 hours which was again confirmed to be associated with cell death and ROS production by trypan blue and DAB staining, respectively. Further, TdT-mediated dUTP nick-end labelling (TUNEL) assays on these discs suggested that the cell death was apoptotic. When leaf discs from the transgenic lines were exposed to juglone, discs from some lines showed a clear delay in decolourisation, suggesting a protective effect. Whether these plants are resistant to black Sigatoka is unknown and will require future glasshouse and field trials. The work presented in this thesis provides the first report of the use of anti-apoptosis genes as a strategy to confer resistance to Fusarium wilt and water stress in a nongraminaceous monocot, banana. Such a strategy may be exploited to generate resistance to necrotrophic pathogens and abiotic stresses in other economically important crop plants.

Orientador: Elizabeth Orika Ono / Banca: João Domingos Rodrigues / Banca: Carmen Silvia Fernandes Boaro / Banca: Francisco Pinheiro de Araújo / Banca: Aloisio Costa Sampaio / Resumo: Aspectos anatômicos, fisiológicos e bioquímicos da enxertia de maracujazeiros sobre Passiflora cincinnata Mast. 2011. 104f. Tese (Doutorado) - Instituto de Biociências, UNESP - Universidade Estadual Paulista, Botucatu-SP. A espécie Passiflora cincinnata Mast. é considerada potencialmente importante para uso como porta enxerto, uma vez que é tolerante a doenças, nematóides e seca. O presente trabalho teve como objetivos estudar aspectos da anatomia da enxertia de espécies comerciais sobre o porta enxerto Passiflora cincinnata, a influência da enxertia no crescimento inicial de maracujazeiros comerciais e, também, nas respostas ao estresse hídrico. O trabalho constou de três experimentos, no primeiro foi estudado o efeito da exertia sobre o desenvolvimento das plantas de maracujazeiros comerciais (P. edulis f. flavicarpa, P. edulis f. edulis e Passiflora alata). No segundo foram estudados aspectos relacionados à anatomia do caule na região da enxertia durante o processo de pegamento e lignificação em duas espécies de maracujazeiros comerciais (P. edulis f. flavicarpa e P. alata). No terceiro experimento foi estudado o efeito da enxertia nas respostas ao estresse hídrico durante a fase inicial de desenvolvimento das plantas de P. edulis f. edulis para compreender por meio de estudos de trocas gasosas e análises bioquímicas como o estresse hídrico pode afetar a produtividade das plantas de maracujazeiros. Foi possível observar que a influência da enxertia no crescimento inicial das plantas de maracujazeiros e nos teores de minerais foliares variou de acordo com a espécie estudada. Na anatomia foi observada compatibilidade entre o porta enxerto e as espécies copa estudadas, ocorrendo divisão e diferenciação celular já no oitavo dia após a enxertia e, aos 30 dias após a enxertia, os tecidos se apresentavam diferenciados e completamente unidos... (Resumo completo, clicar acesso eletrônico Abaixo) / Abstract: Anatomical, physiological and biochemical aspects related to grafting of passion fruit trees onto Passiflora cincinnata Mast. 2011. 104f. Thesis (Doctorate) - Institute of Biosciences, UNESP - São Paulo State University, Botucatu-SP. The species Passiflora cincinnata Mast. is considered potentially important as rootstock since it is tolerant to diseases, nematodes and drought. The present work aimed to evaluate anatomical aspects related to grafting of commercial species onto the rootstock Passiflora cincinnata and to determine the influence of grafting on the initial growth of commercial passion fruit trees and on the responses to water stress. The study consisted of three experiments. In the first experiment, the effect of grafting was assessed on the development of commercial passion fruit trees (P. edulis f. flavicarpa, P. edulis f. edulis and Passiflora alata). The second experiment aimed to describe aspects related to the stem anatomy in the grafting region during setting and lignification in two species of commercial passion fruit trees (P. edulis f. flavicarpa and P. alata). The third experiment was designed to study the effect of grafting on the responses to water stress during the initial development stage of P. edulis f. edulis plants and understand, using gas exchange and biochemical evaluations, how water stress can affect the productivity of passion fruit trees. The influence of grafting on the initial growth of passion fruit trees and on the leaf mineral levels varied according to the species. Considering the anatomy, there was compatibility between the rootstock and canopy species, with cell division and differentiation occurring already on the eighth day after grafting, and at 30 days after grafting tissues were differentiated and completely joined. As to gas exchange and chlorophyll fluorescence, the greatest differences were between... (Complete abstract click electronic access below) / Doutor

Orientador: Gustavo Habermann / Banca: Gustavo Maia Souza / Banca: Carlos Henrique Britto de Assis Prado / Resumo: Aqui analisamos as diferenças entre plantas irrigadas e não irrigadas de três espécies congenéricas de Styrax que apresentam distribuições geográficas distintas no cerrado, Brasil. Styrax ferrugineus mostrou condutância estomática (gs) não-responsiva à deficiência hídrica do solo aplicada em plantas envasadas. Isso pode explicar as maiores eficiências de trocas gasosas e fotoquímicas encontradas em S. ferrugineus, uma espécie bem adaptada ao cerrado sensu stricto (s. str.) que é um tipo de vegetação savânica. S. camporum, que é amplamente distribuída nas áreas de cerrado sensu lato (s.l.), foi a única espécie que aumentou as eficiências de uso da água nos dias de maior deficiência hídrica. Tal resultado distingue S. camporum de S. pohlii, uma espécie de mata, uma vez que ambas as espécies diminuíram gs durante os dias de maior estresse hídrico. Em contraste a outros estudos, nós propomos que características medidas instantaneamente podem detectar performances não-plásticas aos estresses ambientais, o que auxilia explicar as distintas distribuições geográficas de espécies congenéricas no cerrado / Abstract: Here we analyzed the differences between irrigated and non-irrigated plants of three congeneric Styrax species that present distinct geographical distribution in the cerrado, Brazil. Styrax ferrugineus showed an unresponsive stomatal conductance (gs) to the soil water deficit applied to potted plants. This may explain the great gas exchange and photochemical efficiencies found in Styrax ferrugineus, which is well adapted to the cerrado sensu stricto (s. str.), a savanna-type vegetation. S. camporum, which is widely distributed in the cerrado sensu lato (s. l.) areas, was the only species that presented increased water use efficiencies on the days of maximum water deficit. Such result distinguishes S. camporum from S. pohlii, which is a forest species, since both species decreased their gs during the days of maximum water stress. In contrast to other studies, we propose that instantaneously measured traits may detect non-plastic performances to environmental stresses, which helps to explain distinct geographical distributions of congeneric species in the cerrado / Mestre

Made available in DSpace on 2016-01-26T18:56:23Z (GMT). No. of bitstreams: 1 Dissertacao.pdf: 502487 bytes, checksum: bfc738d62eed60fc6f911a343aa6b5e6 (MD5) Previous issue date: 2011-11-10 / The aim of this work was to evaluate germination, seedling dry matterand germination speed index of Brachiaria humidicola treated with different doses of salicylic acid in two separate experiments. The experiment I consisted of five doses of salicylic acid 0.0, 69.05, 138.1, 207.15, 276.15 mg L-1 diluted in water. Seeds were immersed in solution with salicylic acid for one hour and dried out at room temperature for 24 hours. Seeds were not subjected to any sort of stress. In experiment II were used the best responses in experiment I (69.05, 138.1 mg L-1) and untreated seeds (dried) and soaked in water and then subjected to water stress. Seeds were assessed for for germination at different water potentials (0, -0.3, -0.6, -0.9 MPa) induced by mannitol. Salicylic acid did not improve seed performance when subjected to water stress and even water available. Dry seeds presented better results than any treatment tested. / O objetivo deste trabalho foi avaliar a germinação, a matéria seca de plântulas, e o índice de velocidade de germinação de sementes de Brachiaria humidicola tratadas com diferentes doses de ácido salicílico em dois experimentos distintos. O experimento I compreendeu cinco doses de ácido salicílico 0,0; 69,05, 138,1; 207,15; 276,15 mg L-1 do ácido diluído em água. As sementes foram submersas em solução com ácido salicílico por uma hora, e secas em temperatura ambiente por 24 horas. As sementes não foram submetidas a nenhum tipo de estresse. No experimento II foram utilizadas as melhores respostas obtidas no experimento I (69,05, 138,1 mg L-1 ) e sementes sem tratamento (secas) e embebidas em água, sendo então submetidas a estresse hídrico. As sementes foram avaliadas quanto ao teste de germinação em diferentes potenciais hídricos (0; -0,3; -0,6; -0,9 MPa), induzidos por manitol. O ácido salicílico não melhorou o desempenho das sementes quando submetidas ao estresse hídrico e mesmo com água disponível. Sementes secas apresentaram melhores resultados que qualquer tratamento testado.

Made available in DSpace on 2016-07-18T17:51:07Z (GMT). No. of bitstreams: 1 Dissertacao.pdf: 502487 bytes, checksum: bfc738d62eed60fc6f911a343aa6b5e6 (MD5) Previous issue date: 2011-11-10 / The aim of this work was to evaluate germination, seedling dry matterand germination speed index of Brachiaria humidicola treated with different doses of salicylic acid in two separate experiments. The experiment I consisted of five doses of salicylic acid 0.0, 69.05, 138.1, 207.15, 276.15 mg L-1 diluted in water. Seeds were immersed in solution with salicylic acid for one hour and dried out at room temperature for 24 hours. Seeds were not subjected to any sort of stress. In experiment II were used the best responses in experiment I (69.05, 138.1 mg L-1) and untreated seeds (dried) and soaked in water and then subjected to water stress. Seeds were assessed for for germination at different water potentials (0, -0.3, -0.6, -0.9 MPa) induced by mannitol. Salicylic acid did not improve seed performance when subjected to water stress and even water available. Dry seeds presented better results than any treatment tested. / O objetivo deste trabalho foi avaliar a germinação, a matéria seca de plântulas, e o índice de velocidade de germinação de sementes de Brachiaria humidicola tratadas com diferentes doses de ácido salicílico em dois experimentos distintos. O experimento I compreendeu cinco doses de ácido salicílico 0,0; 69,05, 138,1; 207,15; 276,15 mg L-1 do ácido diluído em água. As sementes foram submersas em solução com ácido salicílico por uma hora, e secas em temperatura ambiente por 24 horas. As sementes não foram submetidas a nenhum tipo de estresse. No experimento II foram utilizadas as melhores respostas obtidas no experimento I (69,05, 138,1 mg L-1 ) e sementes sem tratamento (secas) e embebidas em água, sendo então submetidas a estresse hídrico. As sementes foram avaliadas quanto ao teste de germinação em diferentes potenciais hídricos (0; -0,3; -0,6; -0,9 MPa), induzidos por manitol. O ácido salicílico não melhorou o desempenho das sementes quando submetidas ao estresse hídrico e mesmo com água disponível. Sementes secas apresentaram melhores resultados que qualquer tratamento testado.